DK163806B - Flexible laminate which can be used for packaging purposes - Google Patents

Description

DK 163806B

in

The present invention relates to a flexible laminate for use in packaging purposes, in particular in heat shrink packaging. A particularly valuable application is the use for packing foodstuffs, especially bone-containing 5 fresh red meat.

For many purposes, packaging or packaging materials require high resistance to violence in order to survive externally inflicted violence during transportation and handling of the packaging or packages. When the articles packed in the packaging are not inherently soft or elastic, the packaging can also be subjected to violence resulting from the material packaged therein during transport and handling. An example of goods that are particularly prone to exerting violence on their packaging from the inside is meat pieces containing 15 legs. The packaging material may be punctured due to the relatively hard or pointed legs, which will naturally adversely affect the packaged meat. Also, many other consumer goods require packaging in a material with great resistance to such violent impact.

20 From the description to Danish patent application no.

No. 1390/71, cf. Danish Patent No. 128,013, is known a laminated tubular plastic film for use in the manufacture of heat-sealable heat shrink packaging, namely in the form of a 3-layer laminate comprising the following layers: (i) a substrate which may constitute the inner layer of a bag and which is of oriented ethylene polymer, including polyethylene or an ethylene / vinyl acetate copolymer containing from 2 to 4 weight percent vinyl acetate derived units.

(ii) an intermediate layer of a polymer which melts at the orientation temperature of layers (i) and (iii) and thus is not oriented; and (iii) an additional layer which may constitute the outer layer of the bag and is an oriented mixture consisting of 72% by weight isotactic polypropylene, 0-50% by weight atactic polypropylene and 0-50% by weight polybutene-1.

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U.S. Patent No. 3,567,539 discloses a 2-layer laminate suitable for heat shrinkage embryo age 11 comprising a substrate of irradiated oriented polyethylene and a layer of non-oriented ethylene / vinyl acetate copolymer 5 having a vinyl acetate content of 3 to 28% by weight which is stretched by inflation in the heat above the orientation temperature of the ethylene / vinyl acetate copolymer, so-called "hot-blowing". The heat-coated ethylene / vinyl acetate copolymer coating improves the tear strength of the polyethylene. Peripherally, it is mentioned that both layers may be of the same polymer (but this is not specified more precisely). However, the US patent does not state that this should confer benefits. Moreover, it should be noted that the laminate in question has been found to have poor oxygen barrier properties.

U.S. Patent No. 3,558,330 discloses laminates which are used for wrapping foodstuffs but which cannot themselves be heat shrunk. The layers of the laminate are of non-oriented polymers (cf. column 2, line 62 to column 3, line 3). Some of the laminates described have surface layers 20 of a special low melting point ethylene / vinyl acetate copolymer, namely for heat sealing. The low-melting ethylene / vinyl acetate copolymer resin has a vinyl acetate content of 28% by weight.

It has now been found that a laminate can be obtained which, with respect to the laminates known from the descriptions of the above-mentioned Danish Application No. 1390/71 and US Patent No. 3,567,539, exhibits improved tear strength and improved elasticity. at low temperature, e.g. 3-4.5 ° C. Furthermore, the laminate of the invention has good oxygen barrier properties, is heat shrinkable (as opposed to the laminate known from the aforementioned US Patent No. 3,558,330), and does not suffer from the tendency to delaminate by a heat seal performed after manufacture.

Thus, the invention relates to a flexible laminate having use for packaging purposes and comprising an oxygen barrier layer of a copolymer of vinylidene chloride together with at least 3

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another ethylenically unsaturated monomer, preferably vinyl chloride, which copolymer contains at least 50% by weight of vinylidene dichloride units, and which barrier layer is disposed between one layer of a copolymer of ethylene and 5 vinyl acetate containing 5 to 20, but preferably 8 to 12, by weight, vinyl acetate-derived units and, on the other hand, a layer of an ethylene / vinyl acetate copolymer like the former or a mixture of isotactic polypropylene, atactic polypropylene and polybutene-1, and this laminate is characterized in that the ethylene / vinyl acetate copolymer is at least one. of said layers are oriented.

The ethylene / vinyl acetate copolymer in at least one of the layers of the laminate according to the invention is molecularly oriented, which usually means that the laminate 15 is obtained by stretching an unstretched film of the copolymer.

The ethylene / vinyl acetate copolymers referred to herein comprise (consisting entirely or only as a part) of polymerized ethylene and vinyl acetate units.

Thus, other constituents may be present, the polymer being a terpolymer or a polymer other than a copolymer as long as the predominant parts thereof are derived from ethylene and vinyl acetate. To orient such polymers, it is convenient to first cross-link them. Such crosslinking can be carried out in a manner known per se, e.g.

25 by irradiation.

A method of preparing a laminate of the present invention comprises biaxial stretching of a film of the ethylene / vinyl acetate copolymer, either in the form of a single film or as the outer layer of a laminate. A convenient method is to melt extrude at least one layer of another polymer over an unstretched film of the polymer to form a laminate which is then biaxially stretched.

The laminates of the invention can be prepared as described in DK Patent No. 147,358.

The low oxygen permeability barrier layer, which is particularly important for a packaging laminate, is of a copolymer 4.

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of vinylidene chloride together with at least one other ethylenically unsaturated monomer, this copolymer containing at least 50% by weight of units derived from vinylidene chloride. Such a copolymer is referred to herein as a "vinylidene chloride polymer".

It is desirably a copolymer of vinylidene chloride together with vinyl chloride. It can e.g. contain 70-85% by weight units derived from vinylidene chloride and 30-15% by weight units derived from vinyl chloride. Other monomers suitable for polymerization together with vinylidene chloride to provide a barrier layer are numerous and well known and therefore do not need to be enumerated here.

Laminates containing a barrier layer of vinylidene chloride polymer are known from U.S. Patent No. 3,549,389, CA Patent No. 743,021, and U.S. Patent No. 3,031,332, 15 No. 2,968,576 and No. 2,995,869. In addition, it will be seen that the known laminates have required separate layers to provide the necessary resistance to violence of a single laminate, the necessary adhesive properties of other laminates and the necessary blocking properties of yet another 20 laminates, or it has been necessary to subject such laminates various special treatments to achieve appropriate adhesive properties between the layers. Furthermore, it has hitherto been assumed that ethylene copolymers having a substantial vinyl acetate content would not be satisfactory as outer or inner laminate layers or as coatings which must be resistant to violent influence. It has generally been believed that only those ethylene-vinyl acetate copolymers, whose vinyl acetate content was below 5%, were at all suitable for such purposes. These are just a few of the 30 prior art deficiencies.

Therefore, there is a need for a simple construction laminate with all the necessary properties for packaging purposes, especially for wrapping meat containing bone, without the use of special packaging aids. Precisely with the present invention, laminates are provided that meet this need.

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The vinylidene polymer present in the barrier layer of the laminates of the invention is preferably a mixture of 5-40% by weight of suspension polymer and 60-95% by weight of emulsion polymer, preferably with a blended epoxy resin 5 in an amount of 2-10% by weight, based on the polymer.

An alternative barrier layer material is a melt extruded layer of a quality vinylidene chloride polymer suitable for liquid coating, which is described more fully in DK Patent Application No. 645/73. In a preferred embodiment, the vinylidene chloride polymer suitable as a coating material is present in the barrier layers in an amount of from 5 to 100%, the residue (if present) being comprised of 2-10% epoxy resin as well as a melt extrusion grade vinylidene chloride polymer.

The polymer material for the first layer (substrate) of the laminate is a copolymer of ethylene with vinyl acetate containing 5-20 and preferably 8-12% by weight of units derived from vinyl acetate and having the necessary molecular weight distribution. The third layer, which is to withstand violent influence, is preferably of the same EVA copolymer, preferably also oriented, and may, if desired, be exactly the same as used for the substrate.

The EVA polymer in the substrate layer is preferably cross-linked.

In particular cases, it may be desirable to crosslink the EVA polymer in the substrate layer by measures such as by chemical crosslinking agents. However, in a preferred embodiment, irradiation is used and preferably as further described below. The irradiation time 30 of the ethylene / vinyl acetate copolymer substrate is not critical, but only needs to be sufficient to provide the required dose for cross-linking. In the embodiment described herein, the substrate is preferably irradiated with a dose of 2-15 MR, especially with a dose of 2-10 MR.

The radiation is not limited to electrons from an accelerator, any ionizing radiation being applicable.

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The radiation unit used in the present description is rad, which is defined as the amount of radiation that will emit 10 energies (measured as absorbed energy) per day. grams of irradiated material. The MR unit was designated one million (106) 5 rows.

The oxygen barrier layer preferably adheres directly to the substrate EVA copolymer layer. It is of a vinylidene chloride polymer having at least 50% by weight of units discharged from a vinylidene chloride monomer, preferably a material consisting of 10 copolymers of vinylidene chloride and vinyl chloride having 5-40% units derived from vinyl chloride, in particular 15-30%. This material is preferably 5-40% suspension polymer and 60-95% emulsion polymer and especially 5-15% suspension polymer and 85-95% emulsion polymer. The preferred barrier layer also includes 2-10 and preferably 4-6% by weight, based on the entire layer, of an epoxy resin. Thus, the preferred barrier layer is based on a copolymer of vinylidene chloride with vinyl chloride wherein 5-40% are vinyl chloride derived units mixed with 2-10% epoxy resin, the copolymer itself being a mixture of 5-40% suspension polymer and 60-95. % emulsion polymer. The most preferred barrier layer material comprises (a) a vinylidene chloride / vinyl chloride copolymer with 15-30% vinyl chloride-derived units and (b) 4-60% epoxy resin, which copolymer is a mixture of 5-15% suspension polymer and 85-95% emulsion. 25 polymer.

The term "epoxy resin" refers to a highly viscous epoxy-containing thermosettable resin, which must not be confused with epoxidized oils, which are the usual epoxy resin materials and which are usually formed from epoxidized natural oil and are far less viscous.

It is completely unexpected that the mixture of emulsion and suspension resins, especially those from vinyl-idene polymer, can be melt extruded and formed into good quality biaxially oriented film. Normally, suspension polymerized resin should be expected to cause gels to form in the emulsion resin during extrusion. In the present case 7

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however, the suspension polymer appeared to act as a stabilizer rather than to effect gels in the emulsion polymer film. Without adhering to the following theory, however, it is assumed that the suspension polymer melts slowly in the extrusion chamber and acts as a softener or lubricant during the passage of the mixture through the extrusion apparatus, thus impeding the deposition of the polymer on the surface of the extrusion chamber, thereby preventing its disintegration or degradation. In other words, the emulsion polymer tends to adhere as it melts, and the suspension polymer acts as a kind of slip holder on which it moves. Of course, the entire mixture of copolymers melts and extrudes as such.

It has been found that when the content of the suspension polymer in the polymer mixture exceeds 20%, the orientation of the film becomes difficult. Only with very careful treatment is it possible to use a mixture containing up to 40% suspension polymer. The reason for this difficulty, which appears in the orientation, is that crystals are formed more rapidly in a suspension polymer film. Thus, the suspension polymer acts as a contaminant in the emulsion polymer in the sense that the suspension polymer crystallizes too quickly to obtain an appropriate extraction (film thickness reduction) during the orientation step.

It has now been found possible to operate at extrusion temperatures between the normal treatment conditions for emulsion and suspension polymerized polymers, in other words in the general range of 138-171 ° C for the most preferred compositions. Initially, it was not believed that the mixed materials would be compatible in the state of a molten polymer, namely because of the difference in melt rates of these two polymers.

An alternative preferred material for the carrier layer is a coating material of the type used to deposit a vinylidene polymer coating from a solution or an emulsion. Further, these materials are usually 8

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been applied from solution in a solvent at ambient temperature, after which the layer is dried. This "liquid coating polymer" can be used in place of the suspension polymerized polymer in the above-described preferred barrier layer. It is believed that this "liquid coating" vinylidene polymeric material behaves exactly opposite to the suspension polymer. It has lower melt viscosity and increases the flow of the barrier material in the same way as a lubricant. Liquid coating vinylidene polymers 10 are not considered melt extrudable. In yet other cases, it has been found possible to use the "liquid coating" vinylidene polymer in place of all the vinylidene polymer in the material and form the barrier layer by melt extrusion. Unsurprisingly, it is possible to produce a good movie 15 in this way. Liquid coating vinylidene polymer is usually emulsion polymerized as well, but has proven a peculiar character in the art. Preferably, this vinylidene polymer contains from 5 to 15% by weight of vinyl chloride-derived units.

A third, non-violent impact resistant layer is preferably adhered directly to the oxygen barrier layer to form a three-layer tube laminate. The abrasion-resistant layer is preferably of a composition selected from those mentioned above during the discussion of the substrate layer. Although it need not have the same composition as the substrate layer, it is conveniently the same material.

The laminate according to the invention is preferably stretched in both transverse and longitudinal directions in a stretch ratio of preferably 1: 1.5-1: 6, especially 1: 2-1: 4, which corresponds to a biaxial orientation of 1: 2.25-1, respectively. : 36 and 1: 4-1: 16. The thickness of the layers is reduced in virtually equal proportions.

The substrate layer of the laminate according to the invention preferably has a thickness of 12-125 µm, especially 25-50 µm. The barrier 35 relay preferably has a thickness of 1.25-50 µm, especially 2.5-6 µm. The anti-violent impact resistant layers, such as 9

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preferably the outer protective layer of the tube is 2.5-100 µm thick, especially 6-25 µm thick. These three layers can be directly joined together without an intermediate or interposed layer. The laminate has a shrinkage stress of usually 14-35 kg / cm 2 and preferably 14-28 kg / cm 2 as well as a free shrinkage of at least 40% and preferably of at least 50% at 96 ° C and a free shrinkage of at least 20% and preferably at least 30% at 85 ° C.

A tubular film made from the laminate according to the invention provides an excellent barrier or barrier bag, the substrate layer adhering very nicely to itself at temperatures between 93 and 177 ° C, practically without distortion when this film is heat sealed by a thermal -impulsforseglingsapparat.

The substrate layer also gives the bag excellent puncture strength. The thin barrier layer provides the necessary barrier properties at minimum thickness and at minimal cost. The coating of unirradiated copolymer gives the bag a high degree of resistance to violence at low temperatures and improved tear strength.

An advantageous method of using bags made by the laminate of the invention is described in U.S. Patent No. 3,552,090. After the bags have been evacuated, they are conveniently closed by sealing, e.g. as shown in U.S. Patent No. 3,383,746. A convenient evacuation means is disclosed in U.S. Patent No. 3,628,576.

The use for which the above laminate is specifically designed, although it may have many other uses, is as packaging material for wrapping cut fresh red meat with bare legs. For such purposes, one of the above-mentioned materials made of three-layer laminate must be used. A laminate with a different and inferior barrier layer could possibly be used, but this would imply the deterioration of the workability of the material in the manufacture of the laminate and the quality of the laminate. The laminate is non-toxic and generally suitable for food packaging. It will be understood that when a bag 10

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used to wrap a piece of fresh red meat which is not frozen and which is not to be frozen but packaged and kept at refrigerator temperatures, e.g. from o to 7 ° C, the laminate encloses the cut or cut meat piece 5 and is thus exposed to bone or bone splinters penetrating the inner layer of the bag.

In the preferred packaging method, meat containing bone is placed in the biaxially oriented three-layer laminate which is heat shrinkable. The laminate thus encloses a cut piece of meat containing bone which, depending on the cut or cut of the meat, can always expose the laminate to protruding legs which may be pointed or sharp after chopping. The bag is evacuated and sealed so that the vacuum is maintained. The bag is then heat shrunk tightly around the 15 meat.

In the preferred application of the laminate according to the invention, it is important that the radiation dose be within the stated limits, as this provides an adhesive coating with sufficient tensile strength to provide good workability, good resistance to bone-induced puncture and good orientation of the laminate. . Radiation should be sufficient to increase the tensile strength without greatly reducing the elongation at break as the material must be able to stretch across the bone when used for packaging 25 fresh red meats containing cut legs. At the same time, it is desirable that the bag adapts closely to soft meat and bones, wherever bones protrude from the meat. Fresh red meat can be soft and allow the leg to "swim" therein.

If the film is irradiated too much, the elongation of the fracture goes down, 30 and the leg will break through the packaging after penetration thereon. If the vinyl acetate content is above the above, the polymer melting point decreases, adversely affecting the high temperature properties required for shrink packaging.

35 In addition to the loss of resistance to violent influence being lost at heat shrinkage temperatures, heat sealing 11

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the laminates are delaminated when the vinyl acetate content is well above 18% in this particular laminate. If the vinyl acetate content falls below 5%, the low temperature elasticity decreases and the modulus of elasticity is increased to such an extent that the 5 bag no longer functions as necessary for efficient packaging.

The laminate has a number of highly desirable properties, which typically include good shrinkage at moderately elevated temperature, a break elongation of at least 50% and preferably 100-125%, an oxygen transmission rate of not more than 70 cm 3 / m 2/24 h / 1 atm. at 22.8 ° C and 0% relative humidity (as tested by ASTM D 1434) and usually not above 25 cm3 / m2 / 14 hours / 1 atm. at 22.8 ° C and 0% relative humidity (ASTM D 1454). In its preferred form, the laminate 15 has a ball breaking strength of at least 25 kg * cm, measured on a "Ball Burst Taster No. 13-8" from Testing Machines Inc. while using a standard hemisphere head.

The various layers of the laminate according to the invention may thus comprise compatible additives such as stabilizers, pigmentation agents and processing aids such as waxes, deodorizers, antistatic agents and antiblocking agents. The barrier layer may contain e.g. up to 4% by weight of plasticizer as illustrated in Example 8.

The following examples serve to illustrate the present invention.

CTrggmpftl 1

An ethylene / vinyl acetate copolymer containing 10% vinyl acetate and having a melt index of approx. 2, and which is marketed by the US Industrial Chemicals Division of National Distillers under the trade name "UE 637", is fed to an extruder. The extrusion apparatus has a diameter of 8.9 cm and is operated at the following temperatures: rear zone 121 ° C, center chamber 132 ° C, front chamber 143 ° C, coupling piece 149 ° C 35 and nozzle 166 ° C. The worm speed is 37 rpm. and the pressure is 267 kg / cm 2. Nozzle diameter 12

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is 8.9 cm and the circumference of the tube produced is 20.3 cm. The water from a cooling ring has a temperature of 7 ° C. Clamping rollers are operated at a speed per minute. 10.7 m per and the collapsed tube obtained has a thickness of approx. 460 µ.

5 The collapsed tube is passed through an irradiation unit, which is operated at 500 kiloelectron volts, 20 MA and a speed of 10.7 m per second. per minute, four passes are made and the tube receives a dose of approx. 6 megarad.

The irradiated substrate or substrate film is then fed to a coating nozzle where it is coated with a barrier material. This barrier material contains a slightly softened mixture of copolymers of vinylidene chloride with vinyl chloride. The copolymer mixture consists of 10% suspension polymerized and 90% emulsion polymerized copolymer.

The emulsion polymerized copolymer consists of ca. 70% units derived from vinylidene chloride and 30% units derived from vinyl chloride, and the suspension polymerized copolymer consists of approx. 80% units derived from vinylidene chloride and 20% units derived from vinyl chloride. These materials are available from the Dow Chemical Company under the trade name "U.P. 925" (the emulsion polymerized resin) and "S.P.

Other ingredients in the barrier layer are 5% of an epichlorohydrin / bisphenol A epoxy resin sold under the trademark "EPON resin 25828" by Shell Chemical Company and about 0.5% of a microcrystalline resin. Stable paraffin wax available from Sun Chemical Company and sold under the trademark "Wax 5512" These three resins are blended into a fast-running, high-intensity Prodex-Henschel blender and blended to the hopper in an extrusion device which is a 5 The extruder is operated at the following temperatures: rear zone 99 ° C, center zone 127 ° C, front zone 149 ° C, adapter or coupler 141 ° C and nozzle 160 ° C. The worm speed is 34 35 rpm. and the pressure is 390 kg / cm 2, the diameter of the nozzle is 8.9 cm and the circumference of the substrate tube is 20.3 13

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cm. Top rollers are operated at 19.7 m per per minute and a coating with a thickness of 75 µ is obtained.

A third layer is then formed using the same resin as the first layer. The resin is extruded through an extrusion apparatus operated in the same manner as the first layer extrusion apparatus, except that temperatures are as follows: rear zone 121 ° C, center zone 132 ° C, front zone 193 ° C, coupling piece 227 ° C and nozzle 232 ° C. The coating nozzle is of the same construction as the coating nozzle used for the first layer. Bottom rollers are operated with il, o m per. per minute, and water from the cooling ring is 7 ° C. A coating with a thickness of approx. 150 µ.

Biaxial orientation is accomplished by preheating the tube in water to approx. 88 ° C, and the thus heated tube is passed through clamping rollers operated at 5.8 m / s. per minute, for inflatable rollers operated at 21.4 m per minute. about a minute, 10 cm wide tubes between these two sets of rollers are inflated to produce a film width of approx. 41 cm and a film thickness of approx. 61 µ. The tube thus produced is then wound onto a bearing roll which is then converted into bags by sealing the tube transversely and at intervals to produce bottoms in the conventional manner and cutting the tube to the desired bag lengths.

25 Tflr-CiAmpf »1 2

The procedure described above is repeated except that the barrier layer is changed by the addition of 2% 2-ethylhexyl diphenylphosphate plasticizer obtained from Monsanto under the registered trademark "Santicizer 141" and the content of the epoxy resin is reduced to 3%.

Example 3

The procedure of Example 1 is repeated except that the barrier layer composition is 66% vinylidene chloride / vinyl chloride copolymer resin of the brand "UP 925", 30% of a liquid coating vinylidene chloride polymer resin having 14

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is available from the Dow Chemical Company under the trademark "QX 2168", 2% "Epon resin 828" and 2% "Santicizer 141".

Example 4 The procedure of Example 3 is repeated with the exception that the saran in the barrier layer material is "QX 2168" altogether.

Example 5 QCT 6 10 The procedures of Examples 3 and 4 are repeated except that instead of "QX 2168" a liquid coating vinylidene chloride polymer sold by W.R. is used. Grace and Co. under the trademark "Daran CR 6795-H".

Example 7

The procedure of Example 1 is repeated with the exception that instead of the 5% epoxy resin, 5% of an epoxidized soybean oil (which must not be confused with epoxy resin) is used and which is negotiated by Swift and Co. under the trademark "Epoxol 7-4".

Example 8

The procedure of Example 1 is repeated except that 4% 25 2-ethylhexyldiphenylphosphate plasticizer and 1% magnesium oxide are used in place of the 5% epoxy resin.

Example 9

The procedure of Example 1 is repeated except that a mixture of 53.3% by weight isotactic polypropylene (trademark "Novamont F 007"), 33.3% polybutene-1 (trademark "Mobil PB 103") and 13 is used. , 3% atactic polypropylene (trademark "Novamont Lot 2030") to produce the third layer. The atactic and isotactic polypropylene are first added in proper proportion to a Banbury mixer and melt blended for approx. 8 minutes at 204 ° C

15

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and then extruded into a sheet which is cut into pellets. These pellets are combined with polybutylene-1 pellets in a rotating drum and this mixture is added to the extruder for the third layer. This screwdriver is operated at the following 5 temperatures: rear zone 196 ° C, middle zone 204 ° C, front zone 232 ° C, coupler 204 ° C and nozzle 218 ° C.

Testing the resistance of packaging to violence.

The following test method is carried out: all sample bags are pre-coded and conditioned for 24 hours at 7-10 ° C. Randomly selected bags are used for packaging cut right ribs containing meat with legs weighing 11.3 to 13.6 kg. The bags are 41 cm wide and 76 or 81 cm deep.

15 These packages are evacuated and the bags are closed with metal clips, sealed and dried in an air stream. These packages are then inserted into wax-coated corrugated containers with three in each container. These containers are then sealed with nylon monifilament tape.

The individual containers are then subjected to a fall test where they fall from a height of 0.91 m from a moving conveyor belt. The containers are subjected to a transport violence test after being stored at 3 ° C for 24 hours, then shaken for 7.5 minutes at 1 g on a synchronous motion L.A.B. vi-25 vibration tester to simulate 200 km of road transport.

In both tests, the packaging is then pumped up with air and immersed in water to determine any leakage. A leak packaging is judged as failure.

The results given in Table I below are obtained with bags made using the laminates prepared as described in Examples 1 and 2, and compared with bags intended for such packaging purposes and with the same dimensions, but made from conventional films of related 35 nature. These comparison bags are subjected to exactly the same test conditions.

DK 163806 B

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Claims (4)

A flexible laminate for use in packaging and comprising an oxygen barrier layer of a copolymer of vinylidene chloride together with at least one other ethylenically unsaturated monomer, preferably vinyl chloride, which copolymer contains at least 50% by weight of vinylidene dichloride units and which barrier layer is disposed between one side a layer of a copolymer of ethylene and vinyl acetate containing 10 to 20, but preferably 8 to 12, weight percent vinyl acetate-derived units and, on the other hand, a layer of an ethylene / vinyl acetate copolymer like the former or a mixture of isotactic polypropylene , atactic polypropylene and polybutene-1, characterized in that ethylene / vinyl acetate copolymer is oriented in at least one of said layers. The flexible laminate of claim 1, characterized in that the ethylene / vinyl acetate copolymer is oriented by stretching in a ratio of from 1.5 to 1: 6. 20 Flexible laminate according to claim 1, characterized in that the ethylene / vinyl acetate copolymer is crosslinked in at least one of the layers. 25 Flexible laminate according to claim 1 or 2, characterized in that at least one of the ethylene / vinyl acetate copolymer layers is adhered directly to the barrier layer. 30 35